In recent years, progress has been made in the research and development of display devices that use the phenomenon of electroluminescence occurring in organic material. Each subpixel of such a display device includes an anode and a cathode with an organic light-emitting layer therebetween. When the display device is driven, light is produced when holes and electrons recombine within the organic light-emitting layer after injecting holes through the anode and injecting electrons through the cathode.
The organic light-emitting layer is formed by dripping ink that includes organic light-emitting material into regions partitioned by a bank composed of insulating material and then drying the ink. The thickness of the organic light-emitting layer exhibits a correlation with luminance. Therefore, it is desirable to maintain the thickness of the organic light-emitting layer as uniform as possible.
To satisfy this desire, technology has for example been proposed to provide a gap between the bank and the anode provided therebelow in order to balance affinity and repellency in order to achieve uniformity in the thickness of the organic light-emitting layer (Patent Literature 1). Technology has also been proposed to apply surface treatment, such as oxygen plasma treatment, to the surface of the layer beneath the organic light-emitting layer and to apply surface treatment, such as CF4 plasma treatment, to the surface of the bank in order to achieve uniformity in the thickness of the organic light-emitting layer formed in regions surrounded by these surfaces (Patent Literature 2).